On the wave-tossed banks of the Eastern Shore, treasure washes onto the sand every day —ordinary glass thrown into the water decades ago, where it was broken and beaten by the sea for years, emerging finally as rare and beautiful "sea glass."

Some call sea glass "Tears of the Mermaids," and once you see its luminous glow against the sand, you understand why.

My interest began last October, when my sister and niece proposed a sea-glass hunt at Tolchester Beach near Chestertown on the Eastern Shore. I had never heard of sea glass, though a day at the beach sounded lovely.

But this beach wasn't the broad loaf of warm sand on the ocean side of the state. It was primal — a pebbled sliver where wind whipped our faces and passing ships sent us scrambling higher to avoid the wave-wash. I was hooked.

We had the place to ourselves that day, and we spread out to comb different sections of sand. Every so often, we'd huddle to see each other's treasures. I loved the balance of solitude and companionship.

Researching sea glass online after I got home, I discovered that a Chestertown resident, Richard LaMotte, is a nationally recognized expert on sea glass.

LaMotte, who wrote "Pure Sea Glass, Discovering Nature's Vanishing Gems" in 2004, became a collector almost by accident. His wife, Nancy, is an artist and wanted to work with sea glass, so they started combing local beaches. He said they now have about 30,000 pieces of sea glass.

Under the right conditions, LaMotte said, anything made of glass can turn into sea glass, including beer bottles, windshields and medicine bottles.

The Chesapeake Bay's eastern shores have those right conditions — a long period of dense population (more people means more discarded glass), turbulent waves (helped by ship traffic) and beaches with high banks — making Maryland one of the world's best places for sea-glass collecting.

Beachcombing expert

In January, I met LaMotte on an ice-shrouded shore of the Chesapeake near Chestertown. It was a private beach owned by friends who decorate their home with the wonderful artifacts that wash into their lives — antique bottles and sea glass sorted by beautiful color in large bowls.

We scrambled over rocks and fallen limbs to reach the shore.

"It hasn't been scrubbed recently," LaMotte said, meaning that with the edges of the water frozen, no waves had washed up. So any sea glass we found would have been uncovered by wind.

And there was plenty. As soon as we started ambling along the shoreline we spotted shards everywhere. It seemed that every time I bent down to pick up a beautiful piece of sea glass or pottery, I saw another at the edge of my shoe and then another just behind me.

LaMotte pulled out an old plastic bag with handles to hold the collection, plus a small plastic bag for "special pieces." I had never found lavender-colored glass before, but there it was — piece after piece. By the time we were finished, the plastic sagged with the weight of it all.

I found lots of white pieces as well — by far the most common sea glass and often ignored by veteran sea-glass collectors. But LaMotte said that even the white shards have a story to tell.

"It's all a matter of looking at what it represents," he said as we walked. "These white shards — originally that was a bottle that was kind of ugly, just a regular old bottle, but now it's been broken and conditioned into something that's gemlike, that people can actually make jewelry out of.

"So I think the fact that it takes on a second life is kind of fascinating — the fact that it becomes almost like art, after at some point being something that was very unattractive."

Not every shard that washes ashore is highly valued. It should have a patina or "frosting" and no rough edges, though what to keep is a personal decision — and sometimes isn't even sea glass. Besides shards of glass, I keep stones with interesting textures and pottery pieces — all have a history I can only guess at.

Some colors are more prized than others. Orange — which was almost never used in bottle glass — is the rarest find. LaMotte estimates that only 1 in 10,000 pieces collected will be orange.

Beachcombing with LaMotte I found my own necklace of color. Nestled against shards of ice, sea glass sparkled in pastel blue and lavender, lime green, midnight blue and cognac brown. There was no orange, but I was delighted with my beautiful colors.

Art of sea glass

It wasn't hard to imagine the pieces as jewelry, and sea glass is an inspiration for some local artists, including LaMotte's wife, Nancy. Another is Ellie Mercier of Frederick, who has been beachcombing all her life.

"I found my first piece of beach glass when I was about 3 or 4 years old," said Mercier. "It was an amber, heart-shaped shard that resembled the color of honey when held up to the sun."

Over the years, Mercier filled jars and jars of sea glass, until one day she had an inspiration to make it into art.

"A few years ago, my husband and I were exploring a seaside town in California when I saw a sea-glass bracelet in the window of a shop and was breathless. All I could think about the rest of the trip was creating my own jewelry out of sea glass when I got back home," said Mercier, who now owns a sea-glass art shop in Annapolis.

Some collectors do see art on the sand, but for some of us, just spending time on an uncrowded beach, looking for sea glass as the wind tosses our stress to the waves, is a serene pleasure in itself.

Dora Sullivan, the mayor of Cape Charles, Va., and an avid sea-glass collector, sees it that way, too. "I would rather take my boots and a bag and go for a walk than do anything else," she said. "I call it free therapy."

That's a good attitude to have because LaMotte said sea glass is becoming increasingly harder to find. He calls it a "vanishing resource," explaining that since the 1960s, metal and plastic have overtaken glass as containers. And the recent emphasis on recycling has meant less glass is tossed into the sea. Finally, beach erosion and rising water levels eliminate or narrow collecting sites, he said.

LaMotte, who has a busy day job at his family's water-testing company, said he never expected sea-glass collecting to become such a big part of his life. He got so interested in the history of the shards that he studied glass science so he could date pieces.

"The mystery is all in where it came from," Sullivan agreed. "To be able to find a bottle stopper that isn't broken and to know that someone used it 100 years ago — I find it just amazing."

But more surprising than any rare shard of glass or piece of pottery, LaMotte said, are the personal stories that beachcombers share with him that convey a deeper meaning to what they find.

One of his favorites came from a woman he met several years ago.

"She had been through tough financial times and had to sell all of her possessions except for her house and garden, which she loved the most," LaMotte said. "Finally, though, she had to sell her property as well.

"A good friend who had a house by the beach persuaded her to visit and leave her troubles behind for a bit. On her first day there, the woman wandered down to the beach. It was perfectly clear — no stones, no shells — and suddenly a piece of pottery washed up on a wave and landed right on her feet. And on it was a picture of a house and a garden."